Speed cameras installed on a dangerous stretch of road in Bedfordshire may not have snapped a single photo but police say they are a deterrent anyway.
It takes close scrutiny to see the cameras are under wraps
The cameras were put on the A6 in Bedfordshire six months ago.
They are covered in bin liners which will not be taken off for another two weeks.
However police say the cameras, along with mobile camera units, have led to a reduction in the number of drivers speeding.
Police constable Tony Richardson said: "People actually do see the cameras from a distance and obviously aren't aware that they're not working - and they slow down accordingly."
"Unfortunately, it takes cameras to slow people down in the first place.
"We really ought to get drivers to slow down for problems in the road, junctions, other vehicles, etc. without cameras being there."
Police say part of the delay in the cameras being made operational has been an inability to get a power supply to the machines.